September · Early autumn

What to sow in September in Denver

5 crops are in their window this month in Denver — timed to your local frost dates.

Last frost≈ 22 May
First frost≈ 12 Sep
Frost-free days11 days
September averages51°–85°F

Vegetables

1 in season
Rhubarb
Plant crowns · stop picking by midsummer to let the plant recover
Opens 12 Sep

Herbs · nothing to sow this month

Fruit

4 in season
Blackberries
Plant canes · thornless varieties are easiest for small gardens
Opens 12 Sep
Currants
Plant canes · prune out canes older than three years each winter
Opens 12 Sep
Gooseberries
Plant canes · mind the thorns; pick slightly underripe for pies
Opens 12 Sep
Raspberries
Plant canes · ever-bearing types fruit the first autumn
Opens 12 Sep